1. Field of the Invention
The present invention relates generally to angled tissue cutting instruments and, more particularly, to apparatus and methods for straightening the bends of angled tissue cutting instruments.
2. Brief Discussion of the Related Art
Tissue cutting instruments comprising an elongate outer tubular member and an elongate inner member rotatably disposed in the outer tubular member to cut anatomical tissue have become well accepted for use in various surgical procedures. Typically, the inner member has a distal end with a cutting edge and the outer member has an opening through which the cutting edge is exposed to access anatomical tissue to be cut by the cutting edge when the inner member is rotated within the outer member. The cutting edge may have various configurations in accordance with the type of tissue and/or the type of cutting action to be accomplished. In some instances, the distal end of the outer member has a cutting edge cooperable with the cutting edge of the inner member to cut the anatomical tissue as the inner member is rotated. The outer and inner members ordinarily have proximal ends adapted for coupling with a powered surgical handpiece used to rotate the inner member relative to and within the outer member. Many tissue cutting instruments provide for aspiration of anatomical debris through the tissue cutting instrument and/or irrigation at the operative site via an irrigating or flushing fluid supplied along the tissue cutting instrument.
In tissue cutting instruments of the foregoing type, the outer members may be longitudinally or axially straight or may be longitudinally or axially bent, angled or curved depending on the surgical procedure being performed. Where the outer member is longitudinally or axially bent, angled or curved, the inner member is normally provided with a flexible region adjacent or within the bend, angle or curve in the outer member whereby the inner member assumes the longitudinally or axially bent, angled or curved configuration of the outer member while still being rotatable within the outer member. Angled tissue cutting instruments of the latter type are represented by U.S. Pat. No. 177,490 to Fones, U.S. Pat. No. 4,445,509 to Auth, U.S. Pat. No. 4,466,429 to Loscher, U.S. Pat. No. 4,646,738 to Trott, U.S. Pat. No. 5,152,744 and U.S. Pat. No. 5,322,505 to Krause et al, U.S. Pat. No. 5,286,253, U.S. Pat. No. 5,411,514 and U.S. Pat. No. 5,601,586 to Fucci et al, U.S. Pat. No. 5,437,630 to Daniel et al, U.S. Pat. No. 5,529,580 to Kusumoki et al, U.S. Pat. No. 5,620,415 to Lucy et al, U.S. Pat. No. 5,620,447 to Smith et al and U.S. Pat. No. 5,922,003 to Anctil et al.
In most angled tissue cutting instruments, the bend, curve or angle is pre-formed in the outer member as part of the manufacturing or fabrication process and is essentially rigid or fixed. However, U.S. Pat. No. 5,601,586 and No. 5,411,514 to Fucci et al are representative of variable angle tissue cutting instruments in which a longitudinally straight outer member has a spiral relief cut forming a non-rigid bendable section along which the outer member may be bent axially by a user, and the inner member is flexible to follow the bent configuration of the outer member. Accordingly, the Fucci et al patents are representative of angled tissue cutting instruments in which the bend is pre-formed in the outer member subsequent to the manufacturing process and is essentially non-rigid or variable. The Fucci et al patents also disclose bending tools permitting a user to bend the longitudinally straight outer member axially along the non-rigid bendable section to assume various predetermined angles.
The bending tools disclosed in the Fucci et al patents operate by bending a longitudinally straight outer tube into contact with an angled limit surface disposed at a greater angle than the bend angle to be created in the outer tube and then allowing the outer tube to spring back in a direction away from the limit surface to obtain the bend angle. The angles of the limit surfaces specifically provide for a spring back to create a significant positive bend angle in the outer tube, and the bending tools are not designed with limit surfaces capable of providing a spring back for unbending or straightening an already bent or angled outer tube to obtain a longitudinally straightened outer tube.
Angled tissue cutting instruments in which the outer members are pre-formed with an essentially fixed bend, angle or curve may advantageously be precision manufactured with the bend, angle or curve formed with exactitude to extend in a pre-selected direction at a specified location and angle with a predetermined radius of curvature. Accordingly, the outer member can be manufactured with a pre-formed angle, bend or curve that is optimal for the surgical procedure being performed. As an example, the outer member can have a pre-formed bend, curve or angle that is optimal for use of the instrument as an adenoid blade. In many surgical procedures facilitated by an angled tissue cutting instrument, it is preferable that the outer member be pre-formed with the most desirable or advantageous bend, curve or angle for the particular surgical procedure to ensure that the most optimal outer member configuration is used for the particular surgical procedure.
In some surgical procedures, it is desirable to utilize angled tissue cutting instruments to remove anatomical tissue and to thereafter utilize longitudinally or axially straight tissue cutting instruments for further removal of anatomical tissue. In a combined tonsillectomy and adenoidectomy (T&A) procedure, for instance, an adenoidectomy is performed prior to a tonsillectomy to remove all or part of an adenoid using an angled tissue cutting instrument as represented by the adenoid blade disclosed in the aforementioned Anctil et al patent and by the RADenoid® Blade of Medtronic Xomed Surgical Products, Inc. The tonsillectomy is thereafter performed, typically utilizing the same angled tissue cutting instrument or another different tissue cutting instrument in which the outer member is longitudinally or axially straight. Performing the tonsillectomy using the angled tissue cutting instrument that was used for the adenoidectomy, i.e. the adenoid blade, is disadvantageous since longitudinally or axially straight tissue cutting instruments provide better access to the tonsils. Using another different tissue cutting instrument having a longitudinally or axially straight outer member for the tonsillectomy is also disadvantageous for the increased cost associated with an additional instrument and/or the additional surgical time associated with preparing the additional instrument for use. The added steps involved in preparing an additional instrument for use during surgery may include removing the instrument from its package, assembling the inner member of the instrument within the outer member, coupling the inner member and the outer member to the surgical handpiece, and/or removing the angled tissue cutting instrument from the surgical handpiece so that the same handpiece can be coupled with the inner and outer members of the additional instrument. Furthermore, the need to inventory and supply both angled and straight tissue cutting instruments for a surgical procedure imposes a difficult burden on hospitals and other surgical sites.
In various sinus procedures, it is also common for surgeons to initially utilize an angled tissue cutting instrument to remove anatomical tissue and to thereafter utilize a straight tissue cutting instrument to further remove anatomical tissue. The Rad® 40 Curved Blade and the Rad 60 X-TREME™ Curved Blade of Medtronic Xomed Surgical Products are representative of angled tissue cutting instruments which allow access into the frontal recess and maxillary sinus and are popular for use in sinus surgery, particularly superior ethmoid and frontal recess surgery, removal of maxillary polyps, uncinectomy and antrostomy. During sinus surgery where tissue removal is initially effected using an angled tissue cutting instrument, the surgeon will sometimes switch to a longitudinally straight tissue cutting instrument where needed to afford better access for further tissue removal. As discussed above, the need to switch between two different instruments during a surgical procedure presents numerous drawbacks.
Sometimes angled tissue cutting instruments having blades with a particular distal end cutting configuration are available to surgeons without there being available straight tissue cutting instruments having the particular distal end cutting configuration. There arises an unsatisfied need where a surgeon desires to use the particular distal end cutting configuration of an available angled tissue cutting instrument but as a longitudinally straight tissue cutting instrument. Accordingly, an angled tissue cutting instrument may have to be used in a surgical procedure in which use of a counterpart straight tissue cutting instrument would be more preferable.
Where an angled tissue cutting instrument is to be used in a surgical procedure alone or prior to using a longitudinally straight tissue cutting instrument, the need to bend an initially straight outer tube to obtain the angled tissue cutting instrument as required by the Fucci et al patents is undesirable for the additional time and procedural steps added to the surgical procedure. An angled tissue cutting instrument having a bent outer tube obtained using the bending tools of the Fucci et al patents cannot thereafter be reliably straightened for use as a longitudinally straight tissue cutting instrument since the bending tools are incapable of reversely bending a previously bent outer tube with any degree of precision or control to obtain a longitudinally straight outer tube.
It is seen from the above that a need exists for apparatus and methods to effect controlled unbending or straightening of an angled, bent or curved member of an angled tissue cutting instrument to obtain a longitudinally or axially straight tissue cutting instrument therefrom. Apparatus and methods are needed which are capable of accomplishing unbending or straightening of an angled tissue cutting instrument prior to or during a surgical procedure in a brief amount of time using a minimal number of simple procedural steps. In particular, apparatus and methods are needed for unbending or straightening an angled tissue cutting instrument for use as a longitudinally straight tissue cutting instrument during a surgical procedure to ensure that the instrument has both the optimal distal end cutting configuration and the optimal longitudinal profile for the surgical procedure and/or to eliminate the need for surgeons to switch between different instruments during the surgical procedure. There is also a need to reduce the number of different instruments required to be made available for and/or used during a surgical procedure to reduce surgical costs and the burden on hospitals and other surgical sites associated with maintaining and supplying many different instruments. Especially in the areas of T&A procedures and sinus procedures, the need exists for allowing a pre-formed angled tissue cutting instrument to be used in a surgical procedure to remove anatomical tissue and to be thereafter straightened or unbent for further use in the surgical procedure to remove anatomical tissue as a longitudinally straight tissue cutting instrument. There is also a need to permit an available angled tissue cutting instrument having a particular distal end cutting configuration desirable for use in a surgical procedure to be straightened or unbent prior to the surgical procedure to assume a straight longitudinal profile that is more preferable for the surgical procedure than an angled longitudinal profile. There is a further need for an unbending or straightening tool having a contact surface against which an angled member of an angled tissue cutting instrument is reversely bent and then allowed to spring back in a direction away from the contact surface to obtain a longitudinally straight member. An unbending or straightening tool for angled tissue cutting instruments is needed having a contact surface at the proper angle to controllably unbend the angled members of the angled tissue cutting instruments to obtain longitudinally straight members after accounting for spring-back of the members. An additional need prevails for an unbending or straightening tool having a guide template allowing a particular angled member to be matched with the guide template for unbending using an unbending channel of the tool corresponding to the guide template. A still further need exists for an unbending tool having a plurality of unbending channels for angled members of different longitudinal profiles, respectively, and a guide template for each unbending channel to facilitate matching the different angled members with the appropriate unbending channels.